The present invention relates generally to a level sensing and indicating device used for monitoring the level of solid materials within a container, and more specifically, to a device for monitoring the level of salt in a brine tank typically used in water treatment devices, such as a water filtering device or a water softening device. In this respect, such water treatment devices typically utilize a brine solution, i.e. salt water, as a cleaning agent. The brine solution is typically produced in a brine tank which contains salt in either particulate or block form. Water is introduced into the brine tank, therein dissolving some of the salt, and creating the brine solution. At periodic intervals, the brine solution is removed from the brine tank for use in the treatment device. Fresh water is then added to the brine tank to produce a new supply of the brine solution, thereby dissolving more of the salt.
Devices to monitor the level of salt within such brine tanks are shown in U.S. Letters Pat. No. 4,987,409 to Jackson and U.S. Letters Pat. No. 3,102,175 to Eichenberger. These patents generally disclose devices which sense a change in the level of solid material in a tank by using either: (1) a buoyant sensor that measures the difference between the upper level of water and the upper level of the salt within the tank, or (2) a sensor which measures the change in pressure exerted on it by the salt.
A problem with such devices is that they may not function properly if the solid material becomes unevenly distributed in the tank; nor are they particularly suitable for use with salt comprised of blocks rather than granular particles. In this respect, a device using a pressure sensor may prematurely indicate that the salt in the tank is low if blocks of salt resting on the sensor dissolve unevenly and slide off the sensor or off each other. Similarly, a floating sensor device may become prematurely buoyant and falsely indicate that the level of salt is low if the salt becomes unevenly distributed within the tank. The uneven distribution of salt may cause the difference in the level of the water and the upper surface of the salt to be greater on one side of the tank than on the other thus causing the sensor to float. Moreover, the aforementioned patents disclose devices which contain switches disposed within the brine tank in contact with the brine solution and are thus exposed to an extremely corrosive environment which could eventually affect the operation of the switch.
These and other problems are overcome by the present invention which provides a device for sensing the level of salt within a brine tank by using an element to continuously rest on the upper surface of the salt regardless of the water level and regardless of the form or the configuration of the salt within the brine tank.